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Clinton, Trump battle for crucial New Hampshire votes

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Gore lost New Hampshire by a mere 7,211 votes in 2000

Gore, according to Democrats, held one event in New Hampshire as the nominee

(CNN)Hillary Clinton's team was confident in a New Hampshire win on October 24 when Clinton campaigned in Manchester with Elizabeth Warren. One aide told CNN that this would be Clinton's last trip to the state.

But then the FBI announced it was reviewing emails potentially related to her private server, and Clinton's campaign announced last week that she will rally with supporters in Manchester on Sunday.

One key reason? The ghost of Al Gore.

Gore lost New Hampshire by a mere 7,211 votes in 2000, a fraction that infuriated Democrats in the state given how little he campaigned there during the race.

Gore, according to those Democrats, held one event in New Hampshire as the nominee, canoeing with Jeanne Shaheen on the Connecticut River in July.

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Democrats urged Gore to return to the state in the closing weeks of the race, but he declined, and did not dispatch President Bill Clinton -- who won the Granite State in 1992 and 1996 -- to campaign in New Hampshire, either.

This history was not lost on many of Clinton's top aides, some of whom worked for either Bill Clinton or Gore at the time.

Of course, there are other reasons for the trip, one of which is the number of pro-Bernie Sanders Democrats who have been reluctant to back Clinton.

But one aide told CNN on Friday that one of the reasons Clinton was visiting the state less than 48 hours before Election Day was the lessons learned from Gore.

James Taylor will perform at the Manchester event and Khizr Khan, whose son, Army Capt. Humayun Khan, died from a suicide bombing in Baghdad 12 years ago, will speak. Khan was thrust into the national spotlight after he challenged Donald Trump in a speech at the Democratic National Convention.